This 75 year-old woman presented with this lesion below her left eyelid. She had had two biopsies taken from the lesion before undergoing excision. The marking around  the lesion defined the margin of excision.

• What does the picture show and what are the possible causes?


Answer
A lesion with hyperkeratosis.
Hyperkeratosis occurs in a variety of conditions 
including seborrheic keratosis, solar keratosis, 
squamous cell carcinoma and sometimes sebaceous cell carcinoma

• The above picture shows the first biopsy as taken by a junior ophthalmologist. What is the diagnosis?
a
Answer
The specimen shows only keratin which is stained pink
with H&E. In the absence of a full thickness skin biopsy, no diagnosis is possible as keratin can be produced by many disease processes.

• A repeated biopsy revealed a histology similar to the above picture.

What is the diagnosis?
a
Answer
Squamous cell carcinoma. The histology shows abnormal 
cells with pleomorphic and hyperchromatic nuclei. The
presence of keratin pearl or eddy can be seen in the right lower corner.
 
• Why is it necessary to remove clear margin in this patient?

.
Answer
In malignant tumour, dermal infiltration may be present 
without being apparent to the naked eye. To ensure 
complete excision, a clear margin is recommended. 
This is about 3 mm for basal cell carcinoma and 5 mm 
in squamous cell carcinoma.
If it is necessary to preserve tissue, Moh's technique is
used but this is time-consuming and is only available in 
certain centres. The alternative is to perform a two-stage
procedure. The first stage involves tumour excision with
clear margin and the second stage reconstruction of the 
defect with graft or flap once the margin is declared clear
by the histopathologist. This usually means a wait of a few days.